1. Field of the Invention
The present invention relates to a controller of a power converter and an operation method thereof, and particularly to a controller and an operation method thereof that can adjust at least one of conversion efficiency of a power converter, a current value corresponding to over-current protection of the power converter, and stability of the power converter with an output voltage of the power converter accordingly.
2. Description of the Prior Art
In the prior art, a Universal Serial Bus (USB) type C power delivery adapter system 10 (as shown in FIG. 1) can provide different charging conditions to various consumer electronic products through a power converter (not shown in FIG. 1) included in the power delivery adapter system 10. For example, as shown in FIG. 1, the power delivery adapter system 10 can provide 20V voltage and 5 A current to charge a liquid crystal display 12, provide 5V voltage and 1 A current to charge a smart phone 14, and provide 5V voltage and 2 A current to charge a tablet computer 16. That is to say, a secondary side of the power converter needs to output different charging conditions (e.g. 20V/5 A, 5V/1 A, 5V/2 A) to various consumer electronic products. Because the secondary side of the power converter needs to output different charging conditions, if a frequency of a gate control signal controlling a power switch of a primary side of the power converter, a current value corresponding to over-current protection of the power converter, and a direct current (DC) gain of the power converter are not changed with an output voltage of the secondary side of the power converter, the power converter may have lower conversion efficiency, worse the over-current protection of the power converter, and poorer stability. Therefore, how to increase the conversion efficiency and the stability of the power converter, and improve the over-current protection of the power converter becomes an important issue for a user.